The study of the normal function of living organisms and the means by which it is achieved.

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2answers
7k views

Can humans transdermally absorb minerals from ocean water, and if so how much?

According to several studies quoted here, chemicals can be absorbed by the skin transdermally, at least under certain conditions. When it comes to elements in seawater like sodium, magnesium, ...
3
votes
2answers
101 views

Why we have to damage our muscles to build them?

I know that new muscle cells are made when actin fibers are disrupted. My hypothesis is that muscle mass is limited, from birth, and that nutrients (protein) are only directed to grow muscle when ...
1
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0answers
36 views

Is lung size/shape a factor in long-continuous running of animals?

Apart from other factors, does lung shape/structure/size play any role in long-continuous running animals. Is there any similarity in lung structure between different long-continuous running species?
2
votes
2answers
8k views

Why there is a very high drop in pressure from arteries to arterioles?

Laplace law explains why the pressure is the same in aorta and arteries (100). I am thinking why there is so big drop in pressure when going from arteries to arterioles (40-60). Why there is a great ...
2
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1answer
133 views

Are there fishes with a double circulatory system?

Our courseware materials say there are such fishes, but my Internet searches suggests fishes only have a single circulatory system.
0
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1answer
74 views

which organelle produce glycogen phosphorylase and why

I know that Glycogen phosphorylase doesn't produce from rough endoplasmic reticulum in liver cell. But almost every proteins such as insulin receptor, serum albumin, and lysosomal enzyme have to ...
3
votes
0answers
62 views

What is a common body composition in mammals?

The Physiology Of The Racing Greyhound states that most species have about a 40% muscle mass to body mass ratio. Understanding Body Composition puts "optimal fitness" in humans at 16-25% body fat for ...
4
votes
2answers
321 views

What is the relationship between W, X, Y and P, M retinal ganglion cells?

In Guyton and Hall Textbook of Medical Physiology (12e) the retinal ganglion cells (RGCs) are classified into W, X, and Y types. However, in Gray's Anatomy (40th ed.), RGS are subdivided into midget ...
-1
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1answer
83 views

Does exercise really reduce stress in the biological meaning?

It is a very widespread claim, that movement in general helps body to get out stress hormones. It is used as a warning for long sitting at the computer and I also heard it as a pro-vegan argument (We ...
14
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2answers
8k views

Why do we urinate more when we are nervous?

This question is a result of my personal experience... But I guess that is common for many of us. My school timing is 8:00 am to 1:30 pm (usually). During normal school days I typically urinate one ...
5
votes
1answer
141 views

Normal ECG/EKG Measurement?

I'm getting started using ECG using a 3 lead system by iWorx. I have place the leads on my two wrists and the ground on my ankle and have recorded some data into the provided LabScribe 3 software ...
8
votes
3answers
928 views

Where does extra blood come from to fill your muscles during exercise?

Let's say I go to the gym and lift some weights an hour. During this time my arms will grow due to the "pump" -- the extra blood rushing in to feed the muscles. For example, I've measured about 2-3 ...
4
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0answers
81 views

What is the essence of difference of how different chemicals affect the same receptor?

It is known that various chemicals can bind to the same receptor type, producing different effects. Be these chemicals agonists or antagonists, there are more variations in how they influence the ...
2
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0answers
164 views

Size of classical liver lobule across species

A classical liver lobule is made up of a central vein and the portal triads. A typical human liver weighs around 3 lbs. , while a typical bovine liver weighs around 12 lbs. I was wondering if anyone ...
0
votes
1answer
506 views

If a human is stranded with beer but no water, should they drink it? [duplicate]

TL;DR: At what percent (if any) will alcohol dehydrate you more/faster than drinking nothing? Let's contrive a situation for dramatic effect... A human goes out on a boat for a nice sail in the sea. ...
0
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0answers
81 views

Root etiology of non-pituitary low T4 and low TSH

Please note: I'd like to preface this question by stating that this is neither homework nor me seeking medical advice. I am simply trying to understand the biological, physiological root etiology ...
19
votes
2answers
6k views

What is the mechanism behind “acquired” alcohol tolerance?

I can understand natural variation in alcohol dehydrogenase (ADH) in a population leading to variation in rate of inebriation (after controlling for other variables -- e.g., mass, food consumption, ...
3
votes
3answers
686 views

What is the difference between meristem and bud?

Keep reading both terms quite frequently while studying plant physiology. I did some research trying to establish their differences and I learnt that meristems are undifferentiated cells that can ...
5
votes
1answer
185 views

Case study and speculations on the brain of Edward Mordake

I am very interested in the case of the man named Edward Mordake who lived in the 19th century. In particular, he had two faces. If you have not heard of this man, please, search this up as there are ...
10
votes
2answers
644 views

Should we induce fever to assist healing?

I am currently reading "The Fundamentals of Anatomy Physiology" 10th edition, and have found it an incredibly interesting book. I have just been reading about the lymphatic system, and the various ...
6
votes
1answer
176 views

Do people with congenital analgesia feel cold?

There are a few diseases that cause an insensitivity to pain. This question asks about the relationship between the cold and pain, which got me thinking: Is shivering a response driven by the ...
3
votes
1answer
2k views

Is the swimming pool water harmful to frogs who jump in? If so, how?

Here is an odd question: Frogs have permeable skin. Indeed, via capillary action, frogs absorb water through their skin. Chlorine is in principle a harmful substance. I am sure what percentage of ...
1
vote
1answer
65 views

does phagocytosis dependent on opsonization?

does phagocytotic activity of macrophages and neutrophils depends on opsonization by IGg (antibody) and C3 complex,if it does, so then why macrophages and neutrophils are categorized in Innate immune ...
1
vote
1answer
230 views

Drinking soda triggers tingling on a tiny spot on my upper back… but how? [closed]

The title pretty much says it all. Yes, I know it doesn't make sense. That's why I'm baffled. For the past week or two, I've noticed that drinking soda seems to cause a tingling/stinging sensation ...
10
votes
4answers
2k views

Do tall people have more cells?

Within a single species, how does the relative number of cells in the body relate to the relative size of the organism? Let's say we take two humans, one of them is 6 feet tall and the other one is 5 ...
6
votes
1answer
91 views

What is the top speed of muscle contraction?

Currently I am looking into what muscles groups are most used during a football kick. I have a hypothesis that the quadriceps are not as used as most people think because the momentum the swing ...
0
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1answer
6k views

What are the risks of elevating the legs too regularly and when tired?

I started to to think the pathophysiology of elevating legs high next to the wall too often and when you are tired. I think possible manifestations some damage to valves of the veins (No!) because ...
5
votes
1answer
553 views

Would my hands sweat this much if I wasn't wearing gloves?

I've wondered about this for a long time, and hopefully someone here has a reasonable answer. I'm a cell and molecular biologist, and much of my time at the bench is spent wearing (usually nitrile) ...
6
votes
2answers
57 views

Why do epithelial cells arrest in response to serum?

Primary epithelial cells, for example human mammary epithelium, fail to proliferate (arrest) in serum-containing medium. Therefore, a common growth medium for epithelium contains pituitary extract ...
2
votes
2answers
89 views

How do t-lymphocytes become mature if thymus has lost its function?

The development of t-lymphocytes are done by thymus and we also know that the thymus degenerates before puberty and we also know the maximum lifespan of WBC's is 15 days. So, how do t-lymphocytes ...
0
votes
1answer
102 views

Would a human survive eating only living ants?

After reading an admittedly foolish question about 1 googol ants vs. 1000 humans, I had a question. Could a human survive solely on eating ants (common ants, not the stinging kind, or leafcutters etc.)...
2
votes
0answers
21 views

Peculiarity of chemo senses [closed]

We can easily recall our visual stimulus and auditory stimulus but why can't we recall chemical stimulus like smell and pain? We can recall a song or picture but we can't exactly recall smell and ...
5
votes
1answer
403 views

Where do most mutations come from, mitosis or meiosis?

According to this (old) paper there are 10 times more mutations during meiosis than during mitosis. One reason for that is that recombination often causes replication error and therefore mutations. ...
2
votes
1answer
100 views

How does Celiac's Disease cause people to stop growing?

In all of the sites I've looked on, one of the symptoms of Celiac's Disease is the failure to grow in children. Why would an immune attack against gluten cause stunted growth? Celiac.org states: ...
6
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2answers
4k views

How is membrane capacitance related to the increased speed of saltatory conduction?

Here is the original question which inspired my question. As explained by the answers there, the reason saltatory conduction in myelinated neurons is faster than non-myelinated conduction is because ...
2
votes
1answer
55 views

Physiology of tricuspid and bicuspid(mitral) valves

The tricuspid and bicuspid valves are atrioventricular valves. Both are valves that prevent backflow of blood pumped from the atria to the ventricles. However, the former has 3 "flaps" while the ...
2
votes
0answers
217 views

Skin extra sensitive to heat after burn

I just got my finger burnt (first degree burn $\Rightarrow$ I didn't even bother to bear the wound). It didn't hurt much, even when I pressed the wound. However, when exposed to heat (hot water, but ...
5
votes
1answer
168 views

How are smell and taste in fish differentiated?

The senses of taste and smell in different fish classes are described as two distinct senses; smell is mediated by the nasal openings, and taste by epithelial taste buds. They are both forms of ...
15
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1answer
2k views

How did the huge dinosaurs cope with gravity and loads on bones, etc.?

It's very costly to be a huge animal. Your mass grows in cube when you scale up, but you still only have two/four legs to support the same weight. This increases the pressure that your body needs to ...
8
votes
1answer
174 views

Dimensionless number for blood volume

Comments from the question How is the blood volume of a living organism measured without killing it? by @Nico discussed that the time of blood recirculation scales with the size of the organism. I was ...
0
votes
1answer
114 views

How can succinylcholine cause myorelaxation?

I first thought that this is because of prolonged depolarisations. However, I am not sure anymore, because after reading PubChem, the only possible pathways are are Choline agonist. So I would say ...
3
votes
1answer
57 views

How do cold conditions help organ transplants?

Body organs are kept cold in-between explanting them from the donor and implanting them in the new host. How do these cold conditions help organs to stay viable while they haven't fresh blood, energy ...
4
votes
2answers
189 views

Can carnivores survive on a (processed) vegetarian diet? Why or why not?

There are many differences in for example the digestive system between carnivores, herbivores and omnivores. It seems that in certain kinds of species adaptability with respect to diet is possible. ...
1
vote
1answer
361 views

How much heat can a human sustain? [closed]

For how long can a human sustain a temperature of 180 degrees Fahrenheit (82oC) without damage in a confined place? For instance, suppose a person is sitting in a steam-filled room, without external ...
3
votes
2answers
68 views

Determining how much energy a plant takes in?

I asked a question on WorldBuilding.SE, "Are diamond berries possible?". This led to asking a question on Chemistry.SE about the amount of energy required to burn a 1 ct. diamond (−6.527kJ). The ...
22
votes
3answers
440 views

How is the blood volume of a living organism measured without killing it?

How is the blood-volume of an organism measured without killing it? Note:The blood-volume of an organism is defined as the total volume of blood present inside that organism.
8
votes
3answers
219 views

How does one maintain balance sleepwalking?

Anectodal. Feel free to shoot it down. Walking is an acquired skill; As far as I'm concerned exhaustion causes disorientation. Even after waking up it sometimes takes a second or so to get balanced. ...
7
votes
1answer
147 views

Counterintuitive action of Vitamin D?

Vitamin D acts in a way which to me is counterintuitive. It functionally supplemets Parathormone. It in the intestinal tract steps up calcium absorption by altering nuclear gene expression and also ...
9
votes
1answer
264 views

What is the convention for log notation in biology?

I'm reading through some oldish (1980s) papers on length-weight relationships in fish and crustaceans. Many report log-log relationships without specifying whether this is natural log, base 10, etc. ...
9
votes
1answer
2k views

Why is the brain dependent on glucose?

The strict dependence of the (human) brain on glucose has always been puzzling to me. While ketones can substitute for a portion of the brain's energy needs, it cannot substitute completely: blood ...